Toy top



Sept 29, 1959 M. v. SULLIVAN TOY TOP Filed Dec. 26, 1956 FIG. 5'

@ allr lNl/ENTOR By MILES K SULL/VA/V Haw FIG. 7

ATTORNEY TOY TOP Miles V. Sullivan, Summit, NJ.

Application December 26, 1956, Serial No. 630,497

1 Claim. (Cl. 46-64) This invention relates to toy tops and moreparticularly to a toy top of the self-inverting type which when spun inan upright position may be made to automatically invert and spin uponits handle.

One type of top of the above general class has heretofore beenconstructed with uneven weight distribution with respect to the verticalaxis of the body of the top. This uneven weight distribution is createdby diametrically opposite weighted portions located between the handleand horizontal median line and between said median line and the pivotpoint of the top, respectively. It is claimed that these diametricallyopposite weighted portions exert centrifugual forces in the oppositedirections upon the upper and lower portions of the top, when the top isspun rapidly in an upright position, to cause the top to turn over orinvert and spin upon its handle. When this type of top is spun slowly orslower than a critical speed, these centrifugual forces are insuflicientto cause the top to turn over or invert and it will remain spinning inan upright position in the conventional manner. Because it is dilficultto attain the exact critical speed of rotation required for turnover, itis necessary to spin the top at a rate much greater than this criticalspeed when turnover is desired and at a rate much slower than thiscritical speed when turnover is not desired. Because there is such amarked difference between these two speeds of rotation, this top has adefinite disadvantage in that the secret of the operators control overturnover is readily apparent to an observer.

A second type of top of the above general class has heretofore beenconstructed that does not depend upon an uneven weight distribution withrespect to its vertical axis to accomplish automatic turnover. The lowerportion of the body of this type of top is substantially spherical inshape and the force acting to cause the top to invert and spin upon itshandle involves an interaction of a frictional drag near the point ofcontact of the spherical portion of the body of the top and the surfaceupon which it is spun and a precessional torque which is an interactionbetween the torque produced by gravitational force and angular momentum.This second type of top also has a critical speed of rotation requiredfor turnover, that being the speed at which the required frictional dragand precessional torque are produced. This top also suffers the samedisadvantage as the first top described above in that the secret of theoperators control of turnover is readily apparent to an observer.

Thus, with either of the tops described above an observer may predictwhether the top will spin in an upright position or whether it will turnover and spin upon the handle by observing the original speed at whichthe top is spun.

An object of the present invention is the provision of a toy top of theself-inverting type in which the secret of the operators control overturnover is not readily apparent to an observer.

A further object of the present invention is the provision of a toy topof the self-inverting type which,

aired States Patent under the exclusive control of the operator, may bemade to spin in an upright position in the conventional manner or madeto turn over and spin upon its handle without altering the speed atwhich the top is originally spun.

An additional object of the present invention is the provision of a toytop of the above-described type with which the owner and operator maymystify and amaze observers by exercising exclusive power over the toptocause it to spin in an upright position or to cause it to invert andspin upon its handle.

A still further object of the present invention is the provision of atoy top of the second general type described above which regardless ofthe speed at which it is spun can be prevented from turning over andspinning upon its handle.

An additional object of the present invention is the provision of a topof the second general type described above which when made to invert andspin upon its handle will spin there with greater stability.

A still further object of the present invention is the provision of atoy top of the general type described above which is simple inconstruction, economical to manufacture and which is sturdy and capableof withstanding substantial abuse.

In accordance with one aspect of the present invention, 1 havedetermined that control of turnover of a self-inverting top of thesecond type described above may be accomplished by controlling thefrictional drag exerted on such a top by the surface upon which it isspun and, accordingly, the speed of rotation of such a top is immaterialas long as it is spun at a speed above its critical value, i.e., thespeed required for turnover. Furthermore, it is not necessary toeliminate friction entirely in order to attain this control overturnover as it is only necessary to lower it to a point where theinteraction of its force with the precessional torque is insufiicient tocause the top to invert or turn over.

Accordingly, a feature of the present invention relates to controllingthe frictional drag exerted on a self-inverting top by the surface uponwhich it is spun.

More specifically in accordance with this aspect of the presentinvention, the required control over frictional drag in a top of theabove-described type may readily be accomplished by changing the shapeof that portion of the top which is in contact with the surface uponwhich the top is spun. In particular, it is sufiicient to provide asmall area at the bottom of the top whose radius of curvature is smallwith respect to the radius of curvature of the main body of the top.This is advantageously a pivot on which the top can spin with verylittle frictional drag.

Accordingly, another feature of the present invention relates to thechanging of the radius of curvature of that portion of a top whichcontacts a horizontal surface upon which it is spun.

An additional feature of the present invention relates to outwardlyextending a pivot, having a relatively small radius of curvature, fromthe spherical portion of the body of a top of-the self-inverting typedescribed above and for retracting this pivot within the body of thetop.

In accordance with another aspect of the present invention, it isadvantageous to be able to control the turnover of a self-inverting topof the type described above in a secretive and unobvious manner so as toenable the owner thereof to astound and amaze observers by ostensiblyexercising complete power over the turn over of the top.

Accordingly, a further feature of the present invention relates tooutwardly extending a pivot from the spherical portion of the body of atop and for retracting this pivot within the body of the top in anunobvious manner, thus selectively altering the radius of curvature ofthat portion of a top which contacts a horizontal surface upon which itis spun.

In accordance with still another aspect of the present invention, I havedetermined that a self-inverting top of the type which depends upon thefrictional drag and precessional torque for turnover will spin upon itshandle when in its inverted position with greater stability if the endof the handle is convexly curved. Heretofore, such tops have beenconstructed with a cylindrical handle having a flat face upon which thetop spins when it is inverted.

Accordingly, an additional feature of the present invention relates to ahandle in a self-inverting top of the second type described above havinga convexly curved end upon which to spin when in an inverted position.

The above and other objectsand features of the present invention may bemore readily understood from the following description of three specificillustrative embodiments thereof when read with reference to theattached drawing in which:

Fig. 1 is an unassembled axial sectional view of the body and handle ofone illustrative embodiment of the self-inverting top of the presentinvention;

Fig. 2 is an assembled axial sectional view of the body and a sideelevation view of the handle of the top illustrated in Fig. 1 showingthe position of the pivot when retracted;

Fig. 3 is a partial side elevation view of the body of the assembled topillustrated in Fig. 2 showing the position of the pivot when extended;

Fig. 4 is an assembled axial sectional View of the body and a sideelevation view of the slidable pivot pin and the cap therefor of asecond illustrative embodiment of the self-inverting top of the presentinvention;

Fig. 5 is a horizontal sectional view taken on line 55 of Fig. 4;

Fig. 6 is an axial sectional view of the body and side elevation view ofthe pivot pin of the top illustrated in Fig. 4 showing the manner inwhich the pivot pin is inserted into the body; and

Fig. 7 is an assembled axial sectional view of the body and sideelevation view of the pivot pin of a third illustrative embodiment ofthe self-inverting top of the present invention.

The illustrative embodiment of the self-inverting top of the presentinvention shown in Figs. 1, 2 and 3 of the drawing comprises twoseparate parts, body 1 and handle 2 which are assembled by screwinghandle 2 into body 1. As shown, body 1 is substantially globular in formwith a relatively deep and diametrically wide cylindrical recess 3formed therein. In line with the longitudinal axis of recess 3 and atthe bottom thereof, threaded hole 4 is provided which has an unthreadedrelatively small diameter hole 5 extending through the spherical surfaceof body 1. Recess 3 extends downwardly in body 1 to a point such thatthe center of gravity of the assembled top is spaced slightly below thegeometrical center of body 1 to permit the top, when at rest, to as somethe position shown in Pig. 2.

Handle 2 is cylindrical in form and has a knob portion projecting out ofrecess 3 in body 1 adapted to be used for spinning the top, a smallerdiameter threaded portion 7 adapted to be screwed into threaded hole 4in body 1 and a relatively small diameter pivot 8 adapted to extendthrough hole 5 in body 1 to contact a horizontal surface upon which thetop is spun. End surface 9 of handle 2 as shown in Fig. 2 is convexlycurved to stabilize the spinning of the top when it is inverted andspinning upon this surface. The radius of curvature of surface 9 is,however, not critical and may vary substantially from that shown inFig. 1. The length of the knob portion of handle 2 is such that whenhandle 2 is threaded into body 1, the knob portion will project abovebody 1 in a radial direction to a pointwhich permits easygraspingb'et'w'een the thumb and forefinger or second finger by whichthe top may besp un. The length of pivot 8 is such that when threadedportion 7 of handle 2 is screwed into threaded hole 4 in body 1 untilshoulder 6 contacts the bottom of recess 3, pivot 8 will extend throughhole 5 a relatively small distance past the spherical surface of body 1.This distance may, for example, be of the order of one sixty-fourth ofan inch. The diameter of pivot 8 is relatively small and may, forexample, be of the order of one sixteenth of an inch. The radius ofcurvature of the lower end of pivot 8 is small as compared to the radiusof curvature of body 1.

When body 1 and handle 2 are assembled and the top is spun upon ahorizontal surface with pivot 8 retracted into body 1 as shown in Fig.2, the interaction of frictional drag and precessional torque, thelatter of which results from gravitational force and angular momentum,will cause the end of handle 2 at surface 9 to swirl through larger andlarger circles until surface 9 of handle 2 contacts the surface uponwhich the top was spun whereupon the top will raise itself upon surface9 and spin therein in an inverted position. When the top loses speed, itwill right itself again and come to rest in the position shown in Fig.2.

When the top is spun upon a surface with pivot 8 extended in hole 5through the surface of body 1 as shown in Fig. 3, the reduction in thefriction between the spinning top and the surface caused by the smallerarea of pivot 8 in contact therewith will reduce the force of thefrictional drag exerted on the top to a point where this forceinteracting with the precessional torque will be insufficient to causethe top to turn over.

In the operation of the illustrative embodiment of the top shown inFigs. 1, 2 and 3, the owner has positive control over the turnover ofthe top and may determine whether the top will turn over or not whenspun. This control is exercised by screwing handle 2 either clockwise orcounterclockwise a part of a turn to extend or retract, respectively,pivot 8. This may be done while the top is hidden from view ofobservers, for example, while the top is in the palm of the hand, and inthis manner the appearance is given that the owner has magical powerover the top.

The illustrative embodiment of the top shown in Figs. 1, 2 and 3 may beconstructed of wood, metal, plastic or any other suitable material. In apreferred form, body 1 and handle 2 may be of plastic and constructed bytwo separate and simple molding operations after which the top isassembled by screwing handle 2 into body 1. The friction exerted by thethreads and sidewalls of threaded hole 4 against the threads and surfaceof threaded portion 7 of handle 2 is such that the setting of pivot 8,either extended or retracted, will not be altered by the torque appliedto the knob portion of handle 2 when the top is spun.

A second illustrative embodiment of the self-inverting top of thepresent invention is shown in Figs. 4, 5 and 6. This embodiment issimilar to the first embodiment described above in appearance andoverall dimensions and differs only in the manner in which the pivot isextended and retracted. As shown in Fig. 4, this embodiment comprisesthree parts, body 11 with an integral peg 14, slidable pivot pin 12extending therethrough and cap 22 for pivot pin 12. Body 11 issubstantially globular in form with a relatively deep and diametricallywide recess 13 and an integral peg 14 extending from the bottom ofrecess 13 along the longitudinal axis thereof to a point beyond thecircumference of the body. Extending on the longitudinal axis of peg 14from the top thereof on through the spherical surface of body 11 is asmall diameter hole 15 having a larger diameter portion forming a smallcylindrical cavity 16 in peg 14 as shown in Fig. 4. The upper portion ofpeg 14 from point 17 to the top thereof is split by a narrow transverseslot 18 through the axis'of peg 14, thus forming two leg portions joinedat point 17.

As shown in Figs. 4 and 6, pivot pin 12 comprises a small diameterportion 19 adapted to slide in hole 15 of body 11 and extend a smalldistance through the spherical surface of body 11, a stop 20 adapted tofit into cavity 16 in peg 14 to limit the movement of pin 12 to theextent of the clearance between the top and bottom of stop 20 and theupper and lower surfaces of cavity 16 and a portion 21 having a slightlylarger diameter than portion 19 and adapted to receive a frictionalforce from the cylindrical surface of hole 15 between the two legmembers of peg 14.

Cap 22 is installed on pivot pin 12 after the pin is inserted into hole15 of body 11 in the manner to be described below. As shown in Fig. 4,cap 22 has an apron 23 adapted to slidably fit over the end of peg 14 tocover the spacing between the top of peg 14 and the bottom of cap 22.

The length of portion 19 of pivot pin 12 is such that when cap 22 of theassembled top is depressed until the bottom of stop 20 contacts thelower surface of cavity 16, portion 19 of pivot pin 12 will extendthrough hole 15 in body 11 a relatively small distance past thespherical surface of body 11 to provide a pivot upon which the top maybe spun when turnover is not desired. The clearance between the top andbottom of stop 20 and the upper and lower surfaces of cavity 16 is suchthat when pivot pin 12 is moved upward until the top of stop 20 contactsthe upper surface of cavity 16, portion 19 of pivot pin 12 will beretracted entirely within hole 15 in body 11 and when the top is spun onthe spherical surface of body 11 it will invert and spin upon cap 22.

The radius of curvature of the lower end of portion 19 of pivot pin 12which when extended contacts the surface upon which the top is spun issmall as compared to the radius of curvature of body 11. The uppersurface of cap 22 upon which the top spins when inverted is convexlycurved to stabilize the spinning of the top in the inverted position.

The illustrative embodiment of the top shown in Figs. 4, 5 and 6 may beconstructed of wood, metal, plastic or any other suitable material. In apreferred form, body 11, pivot pin 12 and cap 22 are made of plastic byseparate and simple molding operations. Pivot pin 12 is inserted intobody 11 in the manner shown in Fig. 6. As shown in Fig. 6, the two legmembers of peg 14 are separated to permit removal of the mold whichformed hole 15 and cavity 16 in peg 14 and while separated pivot pin 12is inserted. After pivot pin 12 is inserted in hole 15 of body 11, cap22 is then installed on pivot pin 12 by cementing or by any othersuitable means. As a result of the transverse slot in peg 14 and throughthe molding of body 11 of the top, the two leg members of peg 14 exert aspring action toward each other such that when pivot pin 12 is insertedin hole 15 as shown in Fig. 4, the two leg members of peg 14 will exerta frictional force upon portion 21 of pivot pin 12. This force is suchthat the setting of pivot pin 12 either extended or retracted will notbe altered by the torque applied to peg 14 and cap 22 when the top isspun.

Apron 23 of cap 22 covers the gap between the top surface of peg 14 andthe bottom of cap 22 when pivot pin 12 is in a retracted position andthus gives the appearance that peg 14 and cap 22 are one integral part.

The embodiment of the top of the present invention shown in Figs. 4, 5and 6 and described above operates in the same manner as the firstembodiment shown in Figs. 1, 2 and 3. When portion 19 of pivot pin 12 isextended out of body 11, the top will not invert regardless of the speedat which it is spun. When portion 19 of pivot pin 12 is retracted withinbody 11 and the top is spun upon the spherical surface of body 11, thetop will invert and spin upon cap 22.

A third illustrative embodiment of the self-inverting top of the presentinvention is shown in Fig. 7. This embodiment is a modification of thatshown in Figs. 4, 5 and 6 and is similar in appearance and overalldimension. The body 51 with recess 53 and peg 54 having hole 55 andcavity 56 is formed in two pieces by two separate molding operations.Slidable pivot pin 52 with attached spring members 57 and cap 58 withapron 59 is placed in one half of the top and the other half is thenpress fitted or cemented in place. Spring members 57 in addition toproviding a frictional force against the outer walls of cavity 56provide a stop which limits the extension and retraction of pivot pin 52in hole 55 of body 51.

The embodiment of the top shown in Fig. 7 operates in the same manner asthe first two embodiments described above. When a downward force isapplied to cap 58, pivot pin 52 will be extended out of hole 55 in body51 a short distance, the extension being limited when the bottom ofspring members 57 contact the lower surface of cavity 56. Regardless ofthe speed at which the top is spun with pivot pin 52 extended, the topwill not invert or turn over. When pivot pin 52 is retracted within hole55 until the top of spring members 57 contact the upper surface ofcavity 56 and the top is spun on the spherical surface of body 51, thetop will invert and spin upon cap 58 of pivot pin 52.

It is to be understood that control of frictional drag in a top of theself-inverting type in accordance with the present invention is notlimited to the utilization of a retractable pivot to alter the radius ofcurvature of that portion of the top which contacts the surface uponwhich the top is spun. Other arrangements for altering the radius ofcurvature of the top and, hence, attain control over turnover are withinthe scope of the present invention. For example, control over turnoverin this type of top may be accomplished by providing the top with aflexible bottom and means for selectively distorting the bottom to alterthe radius of curvature.

It is to be understood that the three embodiments of the presentinvention described above are illustrative of the application of theprinciples of the invention. Numerous other arrangements may be devisedby those skilled in the art without departing from the spirit and scopeof the invention.

What is claimed is:

A toy top of the self-inverting type comprising in combination, a bodysubstantially globular in form and having a relatively wide and deepcylindrical recess formed therein, said body having a threaded hole inthe bottom of said recess axial therewith and a small diameter throughhole from the bottom of said threaded hole and axial therewith throughthe globular surface of said body, a cylindrical top handle having asmaller diameter threaded end portion adapted to be screwed into saidthreaded hole, said handle projecting centrally out of said recess insaid body along the longitudinal axis thereof to provide a knob withwhich to spin said top, a relatively small pivot on the threaded endportion of said handle, said pivot adapted to be fully extended from andfully retracted into said through hole in said body in response to afraction of a turn of said handle with respect to said body.

References Cited in the file of this patent FOREIGN PATENTS 413,525Great Britain July 19, 1934 889,574 Germany Sept. 10, 1953 1,033,037France Apr. 1, 1953 1,119,682 France Apr. 9, 1956

